Unix is dead. Long live Unix!

Don't expect to see any more big AIX news. This means the last Unix
left is... Linux

Liam Proven
Tue 17 Jan 2023

It's the end of an era. As The Reg covered last week, IBM has
transferred development of AIX to India. Why should IBM pay for an
expensive US-based team to maintain its own proprietary flavor of
official Unix when it paid 34 billion bucks for its own FOSS flavor
in Red Hat?

Here at The Reg FOSS desk, we've felt this was coming ever since we
reported that Big Blue was launching new POWER servers which didn't
support AIX--already nearly eight years ago. Even if it was visibly
coming over the horizon, this is a significant event: AIX is the last
proprietary Unix which was in active development, and constitutes
four of the 10 entries in the official Open Group list.

Within Oracle, Solaris is in maintenance mode. Almost exactly six
year ago, we reported that the next major release, Solaris 12, had
disappeared from Oracle's roadmap. HPE's HP-UX is also in
maintenance mode because there's no new hardware to run it on.
Itanium really is dead now and at the end that's all HP-UX could run
on. It's over a decade since we reported that HP investigated but
canceled an effort to port it to x86-64.

The last incarnation of the SCO Group, Xinuos, is still around and
offers not one but two proprietary UNIX variants: SCO OpenServer,
descended from SCO Xenix, and UnixWare, descended from Novell's Unix.
We note that OpenServer 10, a more modern OS based on FreeBSD 10,
has disappeared from Xinuos's homepage. It's worth pointing out that
the SCO Group was the company formerly known as Caldera, and isn't
the same SCO as the Santa Cruz Operation which co-created Xenix with
Microsoft in the 1980s.

There used to be two Chinese Linux distros which had passed the Open
Group's testing and could use the Unix trademark: Inspur K/UX and
Huawei EulerOS. Both companies have let the rather expensive
trademark lapse, though. But the important detail here is that Linux
passed and was certified as a UNIX (tm). And it wasn't just one
distro, although both were CentOS Linux derivatives. We suspect that
any Linux would breeze through because several many un-Unix-like OSes
have passed before.

Other OSes have passed or probably easily would, though. IBM's z/OS
is alive and well: version 2.5 came out in 2021 and in 2022 Big Blue
started offering cloud instances. z/OS has a Unix-compatible
environment which has passed the compatibility tests so officially,
it's a UNIX (tm), even if that wasn't its original native API.

The "open" in the name "OpenVMS" originally referred to the POSIX
compatibility it gained with version 5, way back in 1991, and was
first applied to the new version for DEC's Alpha CPUs. Last year VMS
Software released version 9.2 for x86-64 hypervisors (and a single
supported box, HPE's DL380).

Ever since Windows NT in 1993, Windows has had a POSIX environment.
Now, with WSL, it arguably has two of them, and we suspect that if
Microsoft were so inclined, it could have Windows certified as an
official Unix-compatible OS.

In our recent story on Beta 4 of Haiku, we said it wasn't really a
Unix. As you can see, there's an editor's note attached to the end
of the story explaining why.

We had heard from Haiku's primary full-time developer, who vigorously
disagreed with our point of view. To his mind, the fact that Haiku
now has strong Unix compatibility, with some of the main Unix
directories present in its filesystem, a quite complete set of Unix
API calls, a Unix shell, and so on, means that Haiku is quite
definitely a Unix. We feel that inasmuch as it's a reimplementation
of BeOS, with its own native filesystem, API, GUI and so on, it's
something different, which offers Unix compatibility as well.

But this illustrates the difficulty of defining precisely what the
word "Unix" means in the 21st century. It hasn't meant "based on
AT&T code" since Novell bought Unix System Labs from AT&T in 1993,
kept the code, and donated the trademark to the Open Group. Since
that time, if it passes the Open Group's testing (and you pay a fee
to use the trademark), it's UNIX (tm). Haiku hasn't so it isn't.
Linux has so it is. But then so is z/OS, which is a direct
descendant of OS/390, or IBM MVS as it was called when it was
launched in 1974. In other words, an OS which isn't actually based
on, similar to, or even related to Unix.

Which means that the last officially trademarked commercial UNIX (tm)
is Apple's macOS 13, which underneath the proprietary GUI layer is
mostly an open source OS called Darwin anyway. The kernel, XNU, is
based on Mach with an in-kernel "Unix server" derived from FreeBSD.

So, as of 2023, open source really has won. There are more Unix-like
OSes than ever, and some very un-Unix-like OSes which are highly
compatible with it, but the official line is, to all intents and
purposes, dead and gone. All the proprietary, commercial Unixes are
now on life support: they will get essential bug fixes and security
updates, but we won't be seeing any major new releases.

Send flowers.

From: https://www.theregister.com/2023/01/17/unix_is_dead/